Screening apparatus



March 26,1935. I G. LlNKE 1,995,992

SCREENING APPARATUS Filed Dec. 14, 193].

Patented Mar. 26, 1935 n V soitEENnv APPARATUS n 7 GerhardLinke,';Magdcburg, Germany, assignor to the firm Fried. Krupp.Grusonwerk Aktiengesellschaft, Magdeburg-Buckau, Germany ApplicationDecember l l, 1931, Serial No. 580,984

InGermany December 12, 1930 3 Claims.

- It has been found that screen cloth which is rigidly fixed in thescreen frame .has a tendency to blinding. On the other hand if thescreencloth is but loosely fitted between cleatsof the screen frame, the clothis-free to setup its own motion or to flap, and thus the screen clothwears out in a relatively. short time, the cloth breaking mostly atthose points where itis clamped down. In addition to this drawback, the

oscillations set up by such a flapping screen cloth areentirelyirregular, nodes or node-lines being formed along the screencloth whereby the same is subjected to severe bending stresses. Whereassome portions of the screen cloth remain tranquil orare only slightlyoscillating, other vportions oscillate with considerable lag in theiroscillation phases, which sometimes differ as much as 180 from those ofthe screen frame.

It is obvious that a screen cloth oscillating. too

irregularly cannot satisfy the severe demands required during thescreening process and that the screening, efficiency must necessarily beimpaired. Above all sucha screen cloth'cannot transportsatisfactorilythe screen-feed.

The present invention has for its object to eliminate the abovementioned disadvantages by the provision of a screening apparatus inwhich the ,subdivision of the entire screen surface into severalindividual fields of vibration is effected 30 by adjustable tuning-incleats. In'this way it is possible to tune-in each of the individualfields of vibration and thus consequently also the entire screen surfaceto the frequency of oscillation imparted to the screening apparatus. AThe accompanying drawing illustrates several Ways in which theinvention'maybe practicall executed. v

Fig. 1 shows a longitudinal section through a screen frame; v 40 I Fig.2 shows the cross section corresponding to Fig. 1.

Fig. 3 shows a'longitudinal section through a different embodiment of ascreen.

.Fig. 4-. is a plan view of Fig. 3. In a screen frame 1, beams 2 aredisposed longitudinally. and tuning-in cleats or supporting rods Y 3'are so arranged as to rest transversely on top of those beams.

'55 rests on the cleats 3 andit is then stretched tight These cleats canbe shifted along the longitudinal axis of the frame and can at willthrough a. tension device acting along the longitudinal axis ofthescreen frame. The tops of the cleats or supporting rods 3 aredisposed at a higher elevation than the ends of the screen cloth 6,thereby forming a crowned screen divided 5 7 into sections. The tensiondevice consists of screws attached to one end of the screen cloth, the

screw heads'passing through the screen frame system dissonant so thatthe amplitudes of oscillation of the screen cloth will-nowhereexceed theproper limit and. that the screenfeed will" be uniformly propelledacross the :screen sur- 20 face. For the satisfactory functioning of thescreening apparatus it is of great importance to render all parts of thesubstructure; of the screen so rigid that no interfering secondaryoscillations can be excited in these parts. This n c required rigiditymay also be accomplished. by

stiffening the said substructure, by 'somefsup- I porting device.

The cleats 3 are also adjustable in their ver- H j s tical positionindependently of each other. In f} this way the propelling velocity ofeach of these, individual screen'parts can be regulated independently.

n Figs. 3 and 4 illustrate a design of this screening apparatus, whichprovides for the adjuster] bility both of the cleats 3 and the beams 2,thus permitting the variation in'area of the fields'of vibration both inlongitudinal and transverse directions, as indicated by the arrows inFig. 4. 40

The top edges of the beams in this case support i thescreen 6. n I

What I claim is:- v j 1. A' vibrating screening apparatus, comprising alongitudinally extending rigid frame, a Y

screening surface disposed upon said frameya plurality of transverselyextending supporting rods for said screening surface mounted. directlyon said rigid frame and having the tops thereof disposed at a higherelevation than theends of .said screening'surface to form a crownedscreen i divided intosections, and means for separately adjusting saidrods longitudinally along said frame to differentsupporting positions,whereby the fleldsfof vibrating surfaces defined PATENT The other end ofthe screen 10 Rio by said supporting rods maybe varied to impartdissonance thereto,

2. A vibrating screen apparatus comprising in a transverse direction, aplurality of aligned recesses at the top edges of said beams, a. plugrality ofsupporting rods for said screening,sur

said rods to different supporting positions whereby the fields ofvibrating surfaces defined by said supporting rods andbel'ams may bevaried.

to impart dissonance thereto; a e

' 3'. In a-vibratingscreening apparatus, a rigid frame, a screeningsurface, transverse rods for supporting said surface across the wholewidth thereof mounted directly on said rigid frame means for separatelyadjusting said rods in the longitudinal direetion of saidscreening'sursupporting rods may be varied to impart dissonance thereto.V i

' GERHARD LINKE.

- and havingthe stops thereoffidisp osed at a higher face supported bysaid beams at'said recesses Q1 'tvdifleient pD Q p i i n w by vthefleldsofyibrating surfaces defined by'said

